Implantable access port including fluid handling features

ABSTRACT

An access port for subcutaneous implantation into a body of a patient is disclosed. The port is typically subcutaneously connected to a catheter, a distal portion of which is disposed within a vein or other vessel of the patient. The port is configured with enhanced fluid handling features to improve fluid flow therethrough while reducing the likelihood of clotting or occlusions in the attached catheter, thus improving system patency. In one embodiment, for instance, an implantable access port is disclosed and comprises a body defining a reservoir, a needle-penetrable septum covering an opening to the reservoir, a stem defining an outlet to the reservoir, and a deformable element included in the reservoir. The deformable element is operably connected to a main portion of the septum and deforms in response to displacement of the septum to counteract a change in volume within the reservoir and prevent blood ingress into the catheter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/837,061, filed Jun. 19, 2013, and titled “ImplantableAccess Port Including Fluid Handling Features,” which is incorporatedherein by reference in its entirety.

BRIEF SUMMARY

Briefly summarized, embodiments of the present invention are directed toan access port for subcutaneous implantation into a body of a patient.The port is typically subcutaneously connected to a catheter, a distalportion of which is disposed within a vein or other vessel of thepatient. Percutaneous access to the port via a needle can enable aclinician to infuse medicaments through the port and catheter into thevessel of the patient. The port is configured with enhanced fluidhandling features to improve fluid flow therethrough while reducing thelikelihood of clotting or occlusions in the attached catheter, thusimproving system patency.

In one embodiment, for instance, an implantable access port is disclosedand comprises a body defining a reservoir, a needle-penetrable septumcovering an opening to the reservoir, a stem defining an outlet to thereservoir, and a deformable element included in the reservoir. Thedeformable element is operably connected to a main portion of the septumand deforms in response to displacement of the septum so as tocounteract a change in volume within the reservoir and prevent bloodingress into the catheter, where it could otherwise clot and occlude thecatheter. Other fluid handling aspects of an access port are alsodisclosed.

These and other features of embodiments of the present invention willbecome more fully apparent from the following description and appendedclaims, or may be learned by the practice of embodiments of theinvention as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the present disclosure will be renderedby reference to specific embodiments thereof that are illustrated in theappended drawings. It is appreciated that these drawings depict onlytypical embodiments of the invention and are therefore not to beconsidered limiting of its scope. Example embodiments of the inventionwill be described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 is a perspective view of an implantable access port according toone embodiment;

FIGS. 2A and 2B are simplified cross-sectional views of an access portaccording to one embodiment;

FIGS. 3A and 3B are various views of a stem of an access port accordingto one embodiment;

FIG. 4 is a cross-sectional view of the stem of FIGS. 3A and 3B;

FIG. 5 is a perspective view of a dual-reservoir access port accordingto one embodiment;

FIGS. 6A-6C are various cross-sectional views of the access port of FIG.5.

FIG. 7 is a cross sectional side view of an access port according to oneembodiment; and

FIGS. 8A and 8B are various cross-sectional views of the access port ofFIG. 7.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

Reference will now be made to figures wherein like structures will beprovided with like reference designations. It is understood that thedrawings are diagrammatic and schematic representations of exemplaryembodiments of the present invention, and are neither limiting nornecessarily drawn to scale.

For clarity it is to be understood that the word “proximal” refers to adirection relatively closer to a clinician using the device to bedescribed herein, while the word “distal” refers to a directionrelatively further from the clinician. For example, the end of acatheter placed within the body of a patient is considered a distal endof the catheter, while the catheter end remaining outside the body is aproximal end of the catheter. Also, the words “including,” “has,” and“having,” as used herein, including the claims, shall have the samemeaning as the word “comprising.”

Embodiments of the present invention are generally directed to an accessport for subcutaneous implantation into a body of a patient. The port istypically subcutaneously connected to a catheter, a distal portion ofwhich is disposed within a vein or other vessel of the patient.Percutaneous access to the port via a needle can enable a clinician toinfuse medicaments through the port and catheter into the vessel of thepatient. Likewise, fluids can be aspirated from the vessel, via thecatheter, port, and needle.

In accordance with one embodiment. the port is configured with enhancedfluid handling features to improve fluid flow therethrough whilereducing the likelihood of clotting or occlusions in the attachedcatheter, thus improving system patency. Further details regarding theseenhancements are given below.

Reference is first made to FIG. 1, which depicts an implantable accessport (“port”), generally designated at 10, configured in accordance withone embodiment. As shown, the port 10 includes a body 12 that defines areservoir (FIG. 2A). A compliant, needle-penetrable septum 14 covers thereservoir and provides needle access thereto. A stem 16 extends from theport body 12 and is configured to operably connect to a proximal end ofa catheter that is in turn disposed in the vasculature of a patient. Inthis way, vascular access to the patient by a clinician is provided viathe catheter, connected access port, and skin-penetrating needle, suchas an infusion set needle, for instance.

FIGS. 2A and 2B show a simplified, cross sectional view of an accessport similar to the port 10 of FIG. 1. In particular, FIGS. 2A and 2Bshow the reservoir 26 that is defined by the port body 12, and themanner in which the septum 14 is disposed in a reservoir opening, oraperture 21, which is defined by the port body such that the septumcovers and isolates the reservoir 26.

In further detail, the septum 14 includes a body 20 and an annularflange 22 that radially extends from a main portion, or central portion,28 of the septum. Note that the main portion as used herein includes anyportion of the septum through which a needle can penetrate during use ofthe port, though the size and extent of the main portion of the septumcan vary in other embodiments. The septum flange 22 is received into anannular groove 32 defined by the port body 12. The groove 32 is disposedproximate the aperture 21 in the present embodiment, and the fit betweenthe flange 22 and the groove is such that the septum 14 is secured inplace so as to sealably enclose the reservoir 26. As shown in FIGS. 2Aand 2B, then, the central portion 28 and flange 22 of the septum body 20extend along a horizontal plane P.

In accordance with the present embodiment, FIGS. 2A and 2B show that theseptum 14 further includes a deformable element, such as a skirt, orcylindrical extension 24, which extends substantially perpendicularlyfrom the plane P of the central portion 28 of the septum body 20. Asshown from the perspective of FIGS. 2A and 2B, the cylindrical extension24 extends circumferentially downward from proximate a junction of thecentral portion 28 and the flange 22 of the septum body 20. As such, acentral axis of the cylindrical extension 24 extends perpendicularlywith respect to the plane P. Note that the location of the cylindricalextension, as well as its geometric shape, size, thickness, etc., canvary from what is shown and described herein.

FIG. 2A further shows that the cylindrical extension 24 of the septum 14is seated within a correspondingly-sized cylindrical recess 34 that iscircumferentially defined about the periphery of the reservoir 26. Anannular bottom portion of the cylindrical extension 24 is affixed to acircumferential attachment surface, which in the present embodiment isdefined by a shoulder 36 at the bottom of the cylindrical recess 34.Such attachment between the shoulder 36 and the bottom portion of thecylindrical extension 24 can be achieved via mechanical affixation,adhesive, or other suitable method.

FIG. 2B shows further details regarding operation of the septum 14, andthe cylindrical extension 24 as a deformable element, during use of theport 10. A hollow needle 38 (such as found in an infusion set) or othersuitable cannula is typically inserted through the septum centralportion 28 such that a distal tip thereof is disposed within thereservoir 26. In this position, the needle 38 can infuse fluids into theport reservoir 26, which fluids then exit the reservoir via the portstem 16 (FIG. 1) and pass through the attached catheter and into thevein or other portion of the patient's vasculature. Once infusion iscomplete, the needle 38 is removed from the septum central portion 28 byexerting an upward pulling force thereon. Because the septum 14 is madefrom a compliant compressible material, such as silicone in oneembodiment, pulling of the needle from the septum 14 causes the centralportion 28 of the septum to deform, or be displaced, in a verticallyupward direction due to compressive friction between the needle and theseptum. An example amount of deformation caused by such needle removalcan be seen by the upward deformation of a bottom surface 28A of thecentral portion 28 of the septum in FIG. 2B as the needle 38 iswithdrawn upward.

Without some form of compensation, the above-described deformation ofthe central portion 28 of the septum 14 as shown in FIG. 2B causes atemporary increase in volume of the reservoir 26. If left unchecked, theincrease in reservoir volume can in turn produce a vacuum force withinthe reservoir. Production of the vacuum force within the reservoir cancause blood from the vein to be aspirated a short distance into thedistal end of the catheter lumen, where it can clot, thus undesirablyoccluding the catheter.

In accordance with one embodiment, the cylindrical extension 24 of theseptum 14 is configured to compensate for the above effects caused byremoval of the needle 38 from the septum. In particular, the cylindricalextension 24 of the septum 14 serves in the present embodiment as acompensation portion to compensate for and negate the increase inreservoir volume and the consequent production of vacuum force withinthe reservoir 26. It is noted that the cylindrical extension 24operates, as described below, about a pivot 39 that is established bythe securement of: 1) the flange 22 of the septum body 20 in the portbody groove 32; and 2) the bottom portion of the cylindrical extension24 to the shoulder 36. So configured, the pivot 39 is a loop definedannularly about an upper portion of the cylindrical extension 24, thoughit is appreciated that the particular shape and location of the pivot 39can vary according to desired cylindrical extension flexing, size andconfiguration of the septum, etc.

The above-described securement of the cylindrical extension 24 and thecorresponding pivot 39 enables the cylindrical extension—which asdescribed in the present embodiment includes compliant silicone and isintegrally formed with the septum central portion 28—to compliantly andlaterally move, i.e., bulge, or flex, radially inward toward the centerof the reservoir 26 in response to the upward deformation of the septumcentral portion 28 described above. The degree of flexing of thecylindrical extension 24 in one embodiment is shown in FIG. 2B, whereinan inner surface 24A of the cylindrical extension bulges radiallyinward. The inward flexing of the cylindrical extension 24 of the septum14 reduces the volume of the reservoir 26, thus compensating for theincreased reservoir volume caused by the septum central portiondisplacement. The net result is that the volume of the reservoir 26remains substantially constant during needle withdrawal from the septum14, and no vacuum force is created therein. Thus, no aspiration of bloodinto the distal tip of the catheter occurs, and the catheter lumenremains patent.

Note that the reservoir in the illustrated embodiment defines an annularcavity 37 about the interior side surface of the reservoir adjacent tothe cylindrical extension so as to encourage separation of thecylindrical extension from a side surface of the reservoir. Though shownin cross section here as semi-circular, the annular cavity 37 can defineother shapes, including square, triangular, etc., and can be positionedin different locations within the reservoir and include different sizes,etc. In yet another embodiment, no annular cavity is included within thereservoir.

Once the needle has been fully retracted from the central portion 28 ofthe septum 14, the central portion resiliently returns to its originalshape, as shown in FIG. 2A, thus causing the cylindrical extension 24 ofthe septum to pivot back to its original, un-flexed configuration, alsoshown in FIG. 2A.

Note that, though they are integrally formed here, in one embodiment thecylindrical extension and septum are separate components but operablymated such that deformation of the central portion of the septum causesthe cylindrical extension to correspondingly flex or move to compensatefor the change in reservoir volume. Also, in one embodiment thecylindrical extension can include two or more pieces that do not fullyencircle reservoir but nonetheless flex inward a sufficient amount tocompensate for the deformation of the septum central portion. Inaddition, the septum can be formed of other resilient materials inaddition to silicone. Note that, in one embodiment, the amount ofcylindrical extension deformation is proportional to the amount ofseptum central portion displacement, given the pivoting action describedherein.

FIGS. 3A-4 are various views of the stem 16 of the port 10 according toone embodiment. As shown, the stem 16 includes a body 40 extendingbetween a proximal end 40A that is inserted into a hole defined in thebody 12 of the port 10 and a distal end 40B that is configured to matewith a proximal end of a subcutaneously placed catheter. The stem body40 defines a fluid conduit 46 that enables fluid to travel from the portreservoir 26 to a lumen of the catheter.

In greater detail, the fluid conduit 46 defines a proximal portion 42extending distally from the proximal end 40A of the stem body 40 and adistal portion 44 extending proximally from the distal end 40B (FIG.3B). In contrast with other stem designs, in the present embodiment thefluid conduit 46 defines a varying diameter configuration, wherein theproximal portion defines a relatively wide first inner diameter ID1proximate the proximal end 40A of the stem body 40, as shown in FIG. 4.The first inner diameter ID1 reduces via a tapered transition region 48to a second inner diameter ID2, which diameter extends through thedistal portion 44 of the fluid conduit 46. The second inner diameter ID2is sized in the present embodiment to enable fluid to be passed into thesubcutaneous catheter attached over the distal end 40B of the stem 16when the port 10 is disposed within the body of the patient.

The gradual transition in inner diameter from large (ID1) to relativelysmall (ID2) as described above in connection with FIG. 4 assists inreducing fluid pressure through the stem 16. This in turn improves flowcharacteristics and opens up options for port, stem, and catheterdesign. Note that, though here shown as having a gradual taper of acertain radius and length, the transition region 48 of the stem fluidconduit 46 can define other gradually changing cross-sectional shapes.Further, the relative sizes of the first and second inner diameters canvary from what is shown and described.

FIGS. 5-6C show details of a dual-reservoir port 50 according to oneembodiment. The port 50 includes a body 52 and two septa 54 eachattached so as to cover an aperture of a respective reservoir 58. A stem56 including a fluid conduit 68 for each of the reservoirs 58 is alsoincluded.

As best seen in FIGS. 6A and 6B, a fluid outlet 60 is interposed betweeneach of the reservoirs 58 and the corresponding fluid conduits 68 of thestem 56. In accordance with the present embodiment and in contrast withknown designs, the fluid outlets 60 are tapered approaching each fluidconduit 68. In particular, each tapered fluid outlet 60 includes twoside walls 62 that converge in a tapered fashion from the reservoir 58toward a conduit entrance 68A of the respective stem fluid conduit 68.In addition, each fluid outlet 60 includes a floor 64 and a top wall 66,as best seen in the cross-sectional views of FIGS. 6B and 6C, which alsoconverge in tapered fashion toward the respective conduit entrance 68A.In other embodiments it is appreciated that the floor, top wall, andside walls can have other positional relationships to one another, suchas a tapering together of only the floor and top walls instead of thetapering of all walls, etc.

The above-described fluid pathway design assists in desirably reducingfluid pressures between the reservoirs 58 and the subcutaneous catheterconnected to the distal end of the stem 56, compared to fluid outletdesigns where the transition from the reservoir to the fluid conduit isrelatively abrupt. Note that the particular degree of taper and size ofthe fluid outlets can be modified from what is shown and describedherein while still residing within the principles of the presentinvention. Also, access ports of various configurations can benefit fromthe tapered fluid outlets described herein, including single-reservoirports and ports with more than two reservoirs. In another embodiment,the tapered fluid outlets include a round cross section or othergeometric shape.

FIGS. 7-8B depict various details regarding an access port according toone embodiment, as shown, the port 10 includes a body 12 that captures aseptum 14 that covers a reservoir 26. A stem 16 defining a fluid conduit17 for the reservoir 26 is also included. As shown in FIG. 7, a movablefloor 72 is disposed within the reservoir 26 in such a way as to besubstantially parallel to a base 70 of the reservoir and to extendacross the two-dimensional dimensions of the reservoir. For instance, inthe case of the reservoir 26 including a round base 70, the floor 72also defines a round two-dimensional shape. Of course, other reservoirand floor two-dimensional shapes are possible. The floor 72 can includea suitable material, such as metal, thermoplastic, etc.

A spring element 74 is interposed between the reservoir base 70 and themovable floor 72 to urge the floor into a height-extended firstposition, as seen in FIG. 7. The spring element 74 can include a springwasher, such as a Belleville washer or cupped spring washer, or othersuitable element to provide a compliant urging force in the upwarddirection (from the perspective shown in FIG. 7) to maintain the floorin the first position of FIG. 7. In the first position, the floor 72causes the reservoir 26 to define a first volume.

The spring element 74 is compressible to enable the floor 72 to bedepressed into a reduced-height second position, shown in FIG. 8A. Thefloor 72 can be depressed by a needle 80 that is inserted through theseptum 14 of the subcutaneously placed port 10. Such insertion of theneedle 80 through the septum 14 and into contact with the floor 72causes the floor to press on and compress the spring element 74 suchthat the floor moves into the reduced-height second position of FIG. 8A.With the floor 72 in this position, the reservoir 26 defines a secondvolume that is greater relative the first volume when the floor is inthe first position. In this position, medicaments or other fluids can beinjected through the reservoir 26 of the port 10 via the needle 80 forpassage through the subcutaneous catheter attached to the stem 16.Similarly, fluids may be aspirated by the needle 80 from the cathetervia the reservoir 26.

Once use of the port 10 is complete, the needle 80 can be removed fromthe septum 14. Removal of the needle 80 also removes the downward forceprovided thereby on the floor 72, which enables the spring element 74 toresiliently expand, causing the floor to rise from the reduced-heightsecond position (FIG. 8A) back to the initial height-extended firstposition shown in FIG. 8B. This upward movement of the floor 72 reducesthe volume of the reservoir 26 from the second volume (FIG. 8A) to therelatively smaller first volume (FIGS. 7, 8B). Such reduction ofreservoir volume forces fluids still present in the reservoir 26 toescape out the conduit 17 of the stem 16 and through the catheterattached thereto, also referred to as a “positive flush.” As a result,any blood or body fluid present in the catheter is flushed out of thecatheter, thus preventing the undesired formation of blood clottingwithin the lumen of the catheter.

Note that other types of springs and resilient components can beemployed for the spring element, and such components can vary in size,number, placement, etc. For instance, more than one Belleville washercan be disposed beneath the floor of the reservoir, in one embodiment.These and other variations are therefore contemplated.

Embodiments of the invention may be embodied in other specific formswithout departing from the spirit of the present disclosure. Thedescribed embodiments are to be considered in all respects only asillustrative, not restrictive. The scope of the embodiments is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes that come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. An implantable access port designed forsubcutaneous implantation, comprising: a body and a needle-penetrableseptum together defining a reservoir, the reservoir including a floorformed by the body, the needle-penetrable septum comprising acylindrical extension forming a wall of the reservoir, the cylindricalextension bending from a straight configuration toward a center of thereservoir upon removal of a previously inserted needle from thereservoir to maintain a substantially constant volume in the reservoir;and a stem defining an outlet to the reservoir.
 2. The access port asdefined in claim 1, wherein the stem includes a conduit for passage offluids through the stem, the conduit defining a proximal conduit portionof a first inner diameter, the proximal conduit portion positioned inthe body of the access port, and a distal conduit portion of a secondinner diameter that is smaller relative the first inner diameter, thedistal conduit portion extending outside of the body of the access port.3. The access port as defined in claim 2, wherein a tapered transitionregion is included in the conduit between the proximal conduit portionand the distal conduit portion.
 4. The access port as defined in claim1, wherein the septum further comprises a main portion from which thecylindrical extension extends, the cylindrical extension extendingsubstantially perpendicularly to a bottom surface of the main portion.5. The access port as defined in claim 4, wherein both the main portionof the septum and the cylindrical extension include silicone and whereinthe cylindrical extension when at rest is seated in a cylindrical recessdefined about a perimeter of the reservoir.
 6. The access port asdefined in claim 5, wherein an annular bottom portion of the cylindricalextension is secured to a portion of the cylindrical recess.
 7. Theaccess port as defined in claim 6, wherein the main portion of theseptum is secured about its perimeter so as to define an annular pivotfor the bending of the cylindrical extension.
 8. The access port asdefined in claim 1, wherein a magnitude of deflection of the cylindricalextension is substantially proportional to a magnitude of displacementof the septum resulting from removal of the previously inserted needle.9. The access port as defined in claim 1, wherein the stem includes adistal portion, a distal-most section of the distal portion including anouter diameter that is larger than a central section of the distalportion.
 10. A method for using an implantable access port, the portincluding a body and a needle-penetrable septum together defining areservoir, the needle-penetrable septum comprising a cylindricalextension forming a wall of the reservoir, and a stem defining an outletto the reservoir, the method comprising: inserting a needle through theseptum to provide fluid access to the reservoir; and removing the needlefrom the septum when fluid access to the reservoir is no longer needed,wherein the removing causes displacement of the septum away from asurface of the reservoir formed by the body and simultaneous inwarddeflection of the cylindrical extension to maintain a substantiallyconstant volume in the reservoir.
 11. A medical method, comprising:obtaining an implantable access port, comprising a body and a septumtogether defining a reservoir, the septum forming a wall of thereservoir, the body forming a floor of the reservoir; implanting theimplantable access port under a patient's skin; piercing the patient'sskin and the septum with a needle to provide fluid access to thereservoir; removing the needle from the septum; and maintaining asubstantially constant volume in the reservoir during the removing bydeflecting a portion of the septum toward a center of the implantableaccess port.